Refined docstring for API of pruners.

[XinyuYe-Intel]

Signed-off-by: Xinyu Ye [email protected]

Type of Change

API helper

Description

detail description JIRA ticket: xxx

Expected Behavior & Potential Risk

the expected behavior that triggered by this PR

How has this PR been tested?

how to reproduce the test (including hardware information)

Dependency Change?

any library dependency introduced or removed